The present invention relates to an internal combustion engine, comprising a valve arranged in the intake duct of the respective cylinder chamber. The valve is located upstream of the cylinder intake valve and, in its closed position, seals the intake duct to prevent the fuel air mixture from flowing into the cylinder chamber during the initial phase of the intake stroke of the respective piston. The valve is controlled at a certain point in time to open the duct so that the fuel-air mixture can flow freely into the cylinder chamber.
Modern automobile engines, which have intake air systems with tuned intake manifolds, have a relatively narrow optimum range for optimum operation, and this must be placed within the R.P.M. range of most frequent engine operation at normal driving speed. At lower engine speeds and even to a certain extent at higher engine speeds, the optimum degree of filling of the cylinder chamber cannot be obtained due to the fact that a sufficient amount of fuel-air mixture is not supplied to the engine cylinders. At low engine speeds, both the engine efficiency and driving comfort will be poorer than within the engine speed range for which the intake manifolds are tuned.
For quite some time, it has been known to utilize so-called delayed charging to increase the degree of filling of the engine and the torque, primarily at low engine speeds, i.e., at rpm values below that for which the intake manifolds are tuned. Delayed or pulse charging can be achieved with the aid of auxiliary valves in the intake manifolds, which auxiliary valves are held closed during the initial phase of the intake stroke, thus creating a negative pressure in the cylinder camber. At a certain point in time, (i.e., according to the principle: the lower the rpm, that much later in the intake stroke), the auxiliary valve is opened, and the fuel-air mixture is allowed to flow into the cylinder. The pulse effect thus provides a "supercharging" which increases the engine torque.
In a known internal combustion engine with delayed charging (e.g., see German Document DE 33 28 879), an auxiliary valve device in the form of a pair of rotatably driven disc-shaped valve elements is disposed in the engine intake manifold The discs have circumferentially extending slots which expose the cross-section of the intake manifold once per revolution. This design thus provides for a gradual exposing of the flow cross-section of the intake manifold when the front edge of the slot moves across the cross-section and a gradual closing when the rear edge of the slot moves across the cross-section.
In general, the faster the auxiliary valve in the intake manifold can open, the greater will be the pulse effect and thus the charging. The purpose of the present invention is to provide, for an internal combustion engine, such an auxiliary valve device which (1) can open more rapidly than the above-described conventional auxiliary valve device, (2) is simple in construction, and (3) can be controlled to precisely adapt its valve times to the current engine speed and load.